Having some serious leaf problems!

Can anyone tell me what is going on with this plant? the leaves are rusty and drying out. I dont think its spider mites. Im using a 5 gallon bubbleponic system trying some diesel ryder autos. theyre about 8 weeks in. Im using bloom nutrients now (started with grow obvi). light schedule of 18/6.

what is going on? she is still growing but now seemingly not as fast because shes losing leaf surface.

Nutrient deficiency. The last time I seen a post like this w/ brown rusty spots on the leaves, it was a calcium and magnesium deficiency.

hi posted my own problem earlier tonight "leaves turning mottled gold help" and ive been looking all night, as some of my leaves are turning rusty, not as bad as yours (yet), but i can see mine going your way, but here and also other forums every one says to add cal mag, also most pages ive read say the same, aparently flush and use cal mag, if you get a chance to look at my thread perhaps you could let me know if yours looked like mine in the begining itd be a great help!!

looks like a pH issue to me, if your pH is in check It kinda looks like Mg def, a really bad one, hmmmm.

check pH and post back.